High-temperature mechanical properties of alloy 718 produced by laser powder bed fusion with different processing parameters

Alexandra Hilaire, Eric Andrieu, Xinhua Wu

Research output: Contribution to journalArticleResearchpeer-review

Abstract

The laser powder bed fusion (LPBF) process produces complex microstructures and specific defects. To build structural components with an acceptable mechanical integrity, optimization of the processing parameters is required. In addition, the evolution of defects under service conditions should be investigated. In this study, the nickel-based alloy 718 was studied in the as-built metallurgical state. Laser processing parameters such as the laser power, scanning speed, and hatch spacing were modified to evaluate their effects on the porosity, microstructure, and mechanical properties at high temperatures. The porosity and pore shape were evaluated using relative density measurements and image analysis. Moreover, the effects of the microstructure and defects on the tensile properties and damaging processes at 650 °C were investigated in air. The results revealed that the loading direction is critical to the mechanical integrity of the alloy, due to the specific orientation of the microstructural interfaces and defects. In addition, from observations of the fracture surfaces, inter-dendritic phases were found to act as crack initiation sites. A tensile test was conducted in vacuum at 650 °C and 2.10 −4 s −1 , and the results indicated that damage processes were not affected by oxidation when the experiments were carried out in air.

Original languageEnglish
Pages (from-to)147-160
Number of pages14
JournalAdditive Manufacturing
Volume26
DOIs
Publication statusPublished - 1 Mar 2019

Keywords

  • Alloy 718
  • Defects
  • High-temperature tensile properties
  • Laser powder bed fusion
  • Processing parameters

Cite this

@article{fe806c8af06e4bcba9c5a27f98697b2a,
title = "High-temperature mechanical properties of alloy 718 produced by laser powder bed fusion with different processing parameters",
abstract = "The laser powder bed fusion (LPBF) process produces complex microstructures and specific defects. To build structural components with an acceptable mechanical integrity, optimization of the processing parameters is required. In addition, the evolution of defects under service conditions should be investigated. In this study, the nickel-based alloy 718 was studied in the as-built metallurgical state. Laser processing parameters such as the laser power, scanning speed, and hatch spacing were modified to evaluate their effects on the porosity, microstructure, and mechanical properties at high temperatures. The porosity and pore shape were evaluated using relative density measurements and image analysis. Moreover, the effects of the microstructure and defects on the tensile properties and damaging processes at 650 °C were investigated in air. The results revealed that the loading direction is critical to the mechanical integrity of the alloy, due to the specific orientation of the microstructural interfaces and defects. In addition, from observations of the fracture surfaces, inter-dendritic phases were found to act as crack initiation sites. A tensile test was conducted in vacuum at 650 °C and 2.10 −4 s −1 , and the results indicated that damage processes were not affected by oxidation when the experiments were carried out in air.",
keywords = "Alloy 718, Defects, High-temperature tensile properties, Laser powder bed fusion, Processing parameters",
author = "Alexandra Hilaire and Eric Andrieu and Xinhua Wu",
year = "2019",
month = "3",
day = "1",
doi = "10.1016/j.addma.2019.01.012",
language = "English",
volume = "26",
pages = "147--160",
journal = "Additive Manufacturing",
issn = "2214-8604",
publisher = "Elsevier",

}

High-temperature mechanical properties of alloy 718 produced by laser powder bed fusion with different processing parameters. / Hilaire, Alexandra; Andrieu, Eric; Wu, Xinhua.

In: Additive Manufacturing, Vol. 26, 01.03.2019, p. 147-160.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - High-temperature mechanical properties of alloy 718 produced by laser powder bed fusion with different processing parameters

AU - Hilaire, Alexandra

AU - Andrieu, Eric

AU - Wu, Xinhua

PY - 2019/3/1

Y1 - 2019/3/1

N2 - The laser powder bed fusion (LPBF) process produces complex microstructures and specific defects. To build structural components with an acceptable mechanical integrity, optimization of the processing parameters is required. In addition, the evolution of defects under service conditions should be investigated. In this study, the nickel-based alloy 718 was studied in the as-built metallurgical state. Laser processing parameters such as the laser power, scanning speed, and hatch spacing were modified to evaluate their effects on the porosity, microstructure, and mechanical properties at high temperatures. The porosity and pore shape were evaluated using relative density measurements and image analysis. Moreover, the effects of the microstructure and defects on the tensile properties and damaging processes at 650 °C were investigated in air. The results revealed that the loading direction is critical to the mechanical integrity of the alloy, due to the specific orientation of the microstructural interfaces and defects. In addition, from observations of the fracture surfaces, inter-dendritic phases were found to act as crack initiation sites. A tensile test was conducted in vacuum at 650 °C and 2.10 −4 s −1 , and the results indicated that damage processes were not affected by oxidation when the experiments were carried out in air.

AB - The laser powder bed fusion (LPBF) process produces complex microstructures and specific defects. To build structural components with an acceptable mechanical integrity, optimization of the processing parameters is required. In addition, the evolution of defects under service conditions should be investigated. In this study, the nickel-based alloy 718 was studied in the as-built metallurgical state. Laser processing parameters such as the laser power, scanning speed, and hatch spacing were modified to evaluate their effects on the porosity, microstructure, and mechanical properties at high temperatures. The porosity and pore shape were evaluated using relative density measurements and image analysis. Moreover, the effects of the microstructure and defects on the tensile properties and damaging processes at 650 °C were investigated in air. The results revealed that the loading direction is critical to the mechanical integrity of the alloy, due to the specific orientation of the microstructural interfaces and defects. In addition, from observations of the fracture surfaces, inter-dendritic phases were found to act as crack initiation sites. A tensile test was conducted in vacuum at 650 °C and 2.10 −4 s −1 , and the results indicated that damage processes were not affected by oxidation when the experiments were carried out in air.

KW - Alloy 718

KW - Defects

KW - High-temperature tensile properties

KW - Laser powder bed fusion

KW - Processing parameters

UR - http://www.scopus.com/inward/record.url?scp=85061096138&partnerID=8YFLogxK

U2 - 10.1016/j.addma.2019.01.012

DO - 10.1016/j.addma.2019.01.012

M3 - Article

VL - 26

SP - 147

EP - 160

JO - Additive Manufacturing

JF - Additive Manufacturing

SN - 2214-8604

ER -